OC950-501-01

OC950-501-01 is a Pacific Scientific component in the OC950 Option Cards series. It provides 21 bidirectional I/O channels for receiving and transmitting digital signals. The channels use 10 kΩ pull-up resistors connected to +12 VDC. The input high threshold is 3.5 V maximum, while the input low threshold is 1.0 V minimum, establishing the voltage levels used to interpret input states. A 100 µs filter time constant helps suppress short-duration input noise.

The outputs use open-drain DMOS transistors and can sink up to 100 mA for connected loads. A 25-contact female D-subminiature connector provides the output connections. The card also supplies a user output of 5 V ±5% with a maximum available current of 200 mA for compatible external circuitry.

Serial communication supports both RS-232 and RS-485 through a 9-contact female D-subminiature connector, allowing connection to devices using either interface standard. Communication uses 10-bit data words without parity. The card contains 32K × 8 NVRAM program memory, which stores program data without continuous power, and its data-retention period is 10 years.